Map is here
Pedro Vial's map of the "Great Spanish Road" began in Natchitoches and passed by homes and ranches of traders/planters. It mentioned several streams/creeks (riachuelo) /bayous/rivers that may not carry the same names anymore. Looking at the map, note the Rancho of the Adaes (the mission/fort which, at this time, had been abandoned by the Spanish) and the Peublo (town) of the Nadaco, a Caddoan tribe. I believe the Sabine River is denoted (las Savinas), and you can also see the Trinity River (Rio of the Trinidad) at the very top of this portion of the map.
Vial mapped a trade route that semi-paralleled the Red River, but he attempted to find the least-water logged area for this new road while also connecting to plantations, ranches, forts, and villages. He sketched this map of the route he took from Natchitoches through dryer land south of the Red River in 1789.
Vial's trading route became known as the "Great Spanish Road," which American map makers alluded to later on. Even Captain Randolph B. Marcy mentioned seeing ruts of the "Spanish Trace" as he made his way to the source of the Red River in 1852. However, there is not a lot written about traders really using this route between Natchitoches and Santa Fe, perhaps because Natchitoches never became a great trading port due to its location just below the Great Raft.
The map is not to scale, and distances aren't true. Vial's map, however, annotated places he'd visit or demarcate for future traders along the route, which is helpful for us in the future to recognize some places.
Since this is a large map found at the Archivo de las Indias in Seville, Spain, I snipped the lower part for your viewing pleasure today.
